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#30
by
jtanguay
on 03 Apr, 2005 11:49
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wouldn't heavier give better fuel mileage though? but suck for accel big time?
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#31
by
QuickTD
on 03 Apr, 2005 17:37
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wouldn't heavier give better fuel mileage though? but suck for accel big time?
How would carrying around and accelerating extra weight improve the fuel economy? A heavy flywheel makes it a bit easier to launch the car and improves idle smoothness a bit, beyond that it is all negative. I cut 2-3lbs off my present flywheel and love it. When change my currently slipping clutch I will cut the flywheel down as much as is possible. I love my 1.9 with the light flywheel. There are no drawbacks that I can see.
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#32
by
jtanguay
on 03 Apr, 2005 20:06
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actually I've heard of buses with huge heavy flywheels for added fuel economy (helps more with stop and go traffic I would assume)
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#33
by
racer_x
on 05 Apr, 2005 09:08
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<snip>
When change my currently slipping clutch I will cut the flywheel down as much as is possible. I love my 1.9 with the light flywheel. There are no drawbacks that I can see.
There is one potential issue with lightened flywheels. The flywheel smooths out the pulses from the power strokes. With a lighter flywheel, the crankshaft speed is more pulsed, especially at low RPM's. This puts some additional stress on the timing belt from the sudden acceleration/deceleration of the engine parts.
With a lighter flywheel, you'll want to check the timing belt more frequently. Look for cracks or wear at the base of the teeth. And you might want to shorten the timing belt change interval some with a lighter flywheel.
I'm not trying to scare you into not running a lighter flywheel. A lighter flywheel does help acceleration a bit. I run a lighter one on my diesel for that reason. I start checking my timing belt at 30,000 miles now, and I changed it at 45,000 miles just to play it safe.
Just be aware that the timing belt is under more stress with the lighter flywheel and don't drive it until the belt snaps.
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#34
by
Mark(The Miser)UK
on 05 Apr, 2005 12:54
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<snip>
When change my currently slipping clutch I will cut the flywheel down as much as is possible. I love my 1.9 with the light flywheel. There are no drawbacks that I can see.
There is one potential issue with lightened flywheels. The flywheel smooths out the pulses from the power strokes. With a lighter flywheel, the crankshaft speed is more pulsed, especially at low RPM's. This puts some additional stress on the timing belt from the sudden acceleration/deceleration of the engine parts.
With a lighter flywheel, you'll want to check the timing belt more frequently. Look for cracks or wear at the base of the teeth. And you might want to shorten the timing belt change interval some with a lighter flywheel.
I'm not trying to scare you into not running a lighter flywheel. A lighter flywheel does help acceleration a bit. I run a lighter one on my diesel for that reason. I start checking my timing belt at 30,000 miles now, and I changed it at 45,000 miles just to play it safe.
Just be aware that the timing belt is under more stress with the lighter flywheel and don't drive it until the belt snaps.
Wouldnt these increased fluctuations create more wear on the engine mountings?
Bugger it... :twisted: "Yes it would" :twisted: Also the torsional stress in the crank will increase. This is what the flywheel is for :lol: I have an ancient manuscript [well1940's]on the theory of damping to help allieviate this vibration that I could post.
Improved economy in buses ... :?: Isn't that from a gyroscope type effect from a freewheeling 'flywheel' that is 'tickled' by using electrically converted breaking force to speed it up and then energy taken back out to help accelerate again. :idea:
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#35
by
16V-Sauger
on 12 Feb, 2006 16:48
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Stan is right... for all-out racing, they use the smallest clutch and flywheel that you can get away with.
Here is the thread where I describe my setup:
http://www.hostboard.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=4037&t=40
I actually have a 200mm setup. But based on my research I actually heard some conflicting opinions on which setup would ultimately be lighter (190mm or 200mm) but for sure either are pounds lighter than a 210mm setup.
The OD of the flywheel is the starter engagement teeth, which is the same for all the clutch diameters. What changes is the OD of the clutch disc (smaller OD = slightly lighter clutch) and the OD of the pressure plate (smaller OD = significantly lighter pressure plate, by like 2 pounds or more going from 210mm to 200 or 190mm.) I have heard that the 190mm, 200mm, and 210mm flywheels should weigh about the same after they've all been lightened to about the max limits, but then again it depends on the skill of the machinist doing the lightening. Where the weighs gets saved by reducing clutch diameter is mainly in the pressure plate.
Here are some pictures of my setup taken from the thread mentioned above:
any comments on such a clutch? is it usable in a daily driver?
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#36
by
fatmobile
on 08 Aug, 2006 01:38
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The links to the old forum aren't working for me.
Let me know if I remember correctly Jake.
You used a 200mm flywheel and the clutch disc is 190mm right?
I've heard some 210mm gasser flywheels have the wrong timing marks for a diesel. Did they use 210mm flywheels with any IDI diesels?
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#37
by
burn_your_money
on 08 Aug, 2006 15:24
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Does anyone have any mileage numbers of before and after adding a lightened flywheel? And also of the claimed torque loss?
Heavy spinning objects require less energy to maintain a constant speed correct? Which would be why a heavier setup would be better for mileage on long highway hauls?
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#38
by
QuickTD
on 08 Aug, 2006 17:16
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Does anyone have any mileage numbers of before and after adding a lightened flywheel? And also of the claimed torque loss?
I didn't notice any difference in mileage before and after the light flywheel, and certainly no loss of torque. Less flywheel inertia makes the car a bit easier to stall on inclines and such but that isn't the same thing as a loss of torque.
Heavy spinning objects require less energy to maintain a constant speed correct?
Incorrect. Heavy spinning objects tend to stay spinning longer when power is removed, but they require the same power to maintain a given speed, and require more power to accelerate. I would guess that a car with a lightened flywheel would be marginally better on fuel, probably not enough to measure though.
And to respond to an earlier post reqarding torque fluctuations and the resultant shortening of timing component life, I can assure you that the timing belt will go the full distance (100000km) with a moderately lightened flywheel, mines done it twice. I also just finished inspecting the stock crank pulley/crank during my most recent timing belt change on my 300000km 1.9TD and it seems none the worse for the light flywheel. Still in excellent condition. I replaced the pulley and the bolt and carried on.
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#39
by
der_panzer
on 11 Aug, 2006 09:38
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my clutch is slippy. engine is a 1990 1.6l TD MF code.
so now i'm going to replace my clutch.. what is my best bet? will the stock 1.6l TD clutch and pressure plate hold upwards of 200ft/Ibs? 180ft/Ibs or there abouts?
FWIW, I use a 210mm ACT organic disc with a VW 16V pressure plate and a lightweight flywheel (8.5 lbs.) on my 85 1.8 turbo gasser. I haven't dynoed the setup, but it in the wintertime it makes enough power to produce wheelspin at any speed through 3rd gear (up to about 90 MPH, since I use a tall AGS tranny.) That's running about 18 PSI, from 3500-7000 RPM.
Even with all that, it doesn't slip. Wonderfully light pedal, too!
I've tried the 6-puck soild ACT disc, and used an ACT pressure plate (3 straps per perch) with the 6-puck and the organic disc, but it was all just overkill. The heavy PP just broke cables, pedal assemblies and release hardware before breaking itself. After all that, I just went with my current setup, and all has been well.
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#40
by
hillfolk'r
on 11 Aug, 2006 15:48
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im runnin a 210mm clutchnet "red" setup
it has a 4 puck ceramic sprung disc
if your guy's idi's cant hold that you are making way more power than my tdi-m
its engagement is smooth,and im runnin a lightened flywheel too
i lightened mine at work,took all that weight off down to the starter ring gear
i drive mine daily
it was like 365 us $
i know the reciept said 377 shipped price on it
it had double straps,or double layers for the parts that hold the pressure plate together
i blew up a centerforce,they are junk,and they have single layer straps
heres a link to my blown up clutch
http://forums.vwvortex.com/zerothread?id=2719718
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#41
by
VolkSport
on 11 Aug, 2006 23:18
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What size flywheel comes stock on a 1985 1.6L TD? If I went to the mentioned 210mm setup with a 16v pressure plate and clutch disc, is it all direct bolt up or does anything have to be changed? Also, is it the 1.8 or 2.0L 16v? Oh, one last question - when you say you lighten it to 8lbs, is that taking 8lbs off of it or it it lightening it to a final weight of 8 lbs? Thanks guys, this info will really help as my clutch is sliping terribly too.
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#42
by
hillfolk'r
on 12 Aug, 2006 10:11
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What size flywheel comes stock on a 1985 1.6L TD? If I went to the mentioned 210mm setup with a 16v pressure plate and clutch disc, is it all direct bolt up or does anything have to be changed? Also, is it the 1.8 or 2.0L 16v? Oh, one last question - when you say you lighten it to 8lbs, is that taking 8lbs off of it or it it lightening it to a final weight of 8 lbs? Thanks guys, this info will really help as my clutch is sliping terribly too.
um,the stock td is a 200 mm
you will need to remark the tdc mark on the new flywheel(210),or you are screwed when you change your timing belt.this is critical
the current tdc mark on 210's isnt correct,you must find tdc,and remark it
mine weighs like 6-7 pounds after lightening it
a 2.0 or 1.8 16v p.p. should be the same
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#43
by
larry104
on 16 Aug, 2006 16:40
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Modding an Eco diesel and I'm concerned about using the stock 200 mm. I know the 16V 210 mm flywheel will work, but the friction disk spline is larger than used on my diesel trans. So my questions are, is an 8V friction disk 210 mm and small spline. And, is there a noticable difference in holding power between the 200 mm and 210 mm clutches. Thank you.
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#44
by
hillfolk'r
on 16 Aug, 2006 21:42
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i dunno,cause i never bothered upgrading a 200 mm clutch to be able to compare holding power to a 210
yea you need a 210 8v disc,a 210 mm flywheel(not nessarily from a 16v )
and a 16v pressure plate
yea a 210 8v is a small spline
get a flywheel from an "83 84 gti"
get a disc for an "83-84 gti)
get a 16v pressure plate
you will be golden,just re mark the flywheel timing mark